A chart disconnect can leave its context endpoint returning over
a closed channel. Exercise the real `_rpc._invoke()` dispatcher
with loopback TCP and a sibling service to isolate the resulting
`TransportClosed` nursery cancellation.
Deats,
- Order caller close, callee EOF and endpoint completion with
events instead of timing sleeps or injected transport errors.
- Keep an ordinary-RPC control for existing response hardening.
- Capture the collateral task, actor/PID, nursery, cancel scope
and cancellation source in a test-generated exception note.
- Record the live IB diagnosis and generated-test provenance.
The ordinary-RPC control passes; the context case remains red
with `ClosedResourceError` wrapped as `TransportClosed`. This
commit establishes the regression before runtime remediation.
Prompt-IO: ai/prompt-io/20261019T140536Z_9a0f220f_final_return_prompt_io.md
(this patch was generated in some part by `opencode` using
`gpt-6.1-sol` (`openai`))
Gud Boi
0553fcf88c